Why Does E=mc2? (And Why Should We Care?)

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Review by:

Oliver K

"A really good introduction to the theory of relativity"

You’ve probably heard of the equation E=mc2, the idea of nothing travelling faster than light and maybe even concepts like clocks slowing down as they get faster, but what do these things actually mean, where do they come from and how do they all relate to each other? ‘Why Does E=mc2?’ explain explains all this, introducing the theory of relativity and showing how simple ideas can have enormous effect on the working of the universe.

Starting from the thought experiment of a bouncing beam of light on train, the book gradually builds up the ideas and concepts behind relativity. It’s written for non-scientists, so everything is explained without the need for any prior knowledge and without any maths more complicated than Pythagoras’ theorem. It then goes on to explain the consequences of relativity from how your mass changes to stop you ever travelling at the speed of light to the idea that objects get smaller as they speed up.

It’s quite hard to understand everything in relativity because some of the results are so unexpected, but part of what makes this book and the whole subject so interesting is seeing how such strange things come from such simple ideas. So if you read this book, don’t worry if there’s the odd paragraph you have to read twice or something you can’t quite get your head around – you’ll still discover some fascinating ideas about how our universe woks!

One thing I particularly like about this book is that, unlike many other popular science books, it doesn’t completely ignore the maths behind the physics. This maths is never too complicated, long or tedious, but it pulls back the curtain on how the underlying theory actually works much better than a description alone can. That said, the book is written so that you can completely skip the calculations if you want to, so you can dip your toes into the mathematical foundations of relativity as much or as little as you want!

I’d definitely recommend ‘Why Does E=mc2?’ if you’re considering Physics at university. It’s a really good introduction to the theory of relativity and gives you a gives you an interesting but easy to understand taste of the maths that underlies one of the most fascinating areas of science!